1. The problem statement, all variables and given/known data Some particle accelerators allow protons (p+) and antiprotons (p-) to circulate at equal speeds in opposite directions in a device called a storage ring. The particle beams cross each other at various points to cause p+ + p- collisions. In one collision, the outcome is p+ + p- yields e+ + e- + γ + γ, where γ represents a high energy gamma-ray photon. The electron and position are ejected from the collision at 0.9999995c and the gamma-ray photon wavelengths are found to be 1.0 X 10-6 nm. What were the proton and antiproton speeds prior to the collision? m(e-)=9.11e-31(kg), λ(γ)=1e-6(nm) 2. Relevant equations Ei = Ef E=mc^2 - 0.5mu^2 E=γmc^2 3. The attempt at a solution I have no ideas how to start and where to start in this question. Please help.